Various workpiece holding devices have been used to positively clamp and hold a workpiece that is to be sewn by an automatic sewing machine. The workpiece is usually registered within the holding device and thereafter positively clamped for sewing. One example of such a device is illustrated in U.S. Pat. No. 3,988,993 to Brophy. This workpiece device utilizes a series of hinged leaves having cavities therein to precisely register various pieces of the workpiece relative to each other. Access by the sewing needle to the registered pieces within the cavities is via openings in the top and bottom leaves of the workholding device. The sewing needle passes through these openings as the workpiece holder is successively positioned underneath the reciprocating sewing needle. It is to be appreciated that the sewing needle must at all times be able to completely pass through a workpiece located within the workpiece holding device. There can, of course, be no interference with the solid metal portions of the workpiece holding device during this penetration of the workpiece. It is to be appreciated that the more extensive the path of the sewing needle becomes, the more difficult it is to provide suitable openings in the top and bottom which would allow for all such sewing to occur.
Other examples of workpiece holding devices are illustrated for instance in U.S. Pat. Nos. 4,171,672 to Dorosz et al and U.S. Pat. No. 4,455,952 to Morin et al. The workpiece devices in these patents have holding members that positively clamp the pieces of work therebetween. These holding members must also allow for penetration of the workpiece by the sewing needle. This often leads to rather complicated shapes which must sufficiently hold one or more pieces constituting the workpiece while allowing the same to be automatically sewn.